diff --git a/tabellio/documents/indexer.py b/tabellio/documents/indexer.py
index 21fa6a1..6ccc9ca 100644
--- a/tabellio/documents/indexer.py
+++ b/tabellio/documents/indexer.py
@@ -56,6 +56,32 @@ grok.global_adapter(documentAuthorsIndexer, name="authorsDoc")
 grok.global_adapter(dossierAuthorsIndexer, name="authorsDoc")
 grok.global_adapter(questionAuthorsIndexer, name="authorsDoc")
 
+def interveningPolgroupsIndexer(obj):
+    return None
+
+documentInterveningPolgroupsIndexer = indexer(IDocument)(interveningPolgroupsIndexer)
+dossierInterveningPolgroupsIndexer = indexer(IDossier)(interveningPolgroupsIndexer)
+questionInterveningPolgroupsIndexer = indexer(IQuestion)(interveningPolgroupsIndexer)
+
+grok.global_adapter(documentInterveningPolgroupsIndexer, name="interveningPolgroupsDoc")
+grok.global_adapter(dossierInterveningPolgroupsIndexer, name="interveningPolgroupsDoc")
+grok.global_adapter(questionInterveningPolgroupsIndexer, name="interveningPolgroupsDoc")
+
+def interveningPersonsIndexer(obj):
+    if not obj.histolines:
+        return None
+    r = []
+    for line in obj.histolines:
+        if not line.authors:
+            continue
+        r.extend([item.to_object.id for item in line.authors])
+    return r
+
+dossierInterveningPersonsIndexer = indexer(IDossier)(interveningPersonsIndexer)
+questionInterveningPersonsIndexer = indexer(IQuestion)(interveningPersonsIndexer)
+
+grok.global_adapter(dossierInterveningPersonsIndexer, name="interveningPersonsDoc")
+grok.global_adapter(questionInterveningPersonsIndexer, name="interveningPersonsDoc")
 
 
 class IAuthorsIndexer(Interface):
diff --git a/tabellio/documents/profiles/default/catalog.xml b/tabellio/documents/profiles/default/catalog.xml
index 39a11b0..8083bb6 100644
--- a/tabellio/documents/profiles/default/catalog.xml
+++ b/tabellio/documents/profiles/default/catalog.xml
@@ -33,12 +33,21 @@
   <index name="publication_date" meta_type="FieldIndex">
     <indexed_attr value="publication_date"/>
   </index>
+  <index name="interveningPolgroupsDoc" meta_type="KeywordIndex">
+    <indexed_attr value="interveningPolgroupsDoc"/>
+  </index>
+  <index name="interveningPersonsDoc" meta_type="KeywordIndex">
+    <indexed_attr value="interveningPersonsDoc"/>
+  </index>
+
   <column value="doctype"/>
   <column value="dostype"/>
   <column value="questype"/>
   <column value="dateDoc"/>
   <column value="polgroupsDoc"/>
   <column value="authorsDoc"/>
+  <column value="interveningPolgroupsDoc"/>
+  <column value="interveningPersonsDoc"/>
   <column value="no"/>
   <column value="nodoc"/>
   <column value="session"/>